Multifetal pregnancy reduction: evaluation of fetal growth in the remaining twins

OBJECTIVE: Our purpose was to study fetal growth after reduction of high-order multiple gestations to twins. STUDY DESIGN: Birth weight and gestational age data were collected for 236 triplet and greater multiple pregnancies reduced to twins (113 triplets, 89 quadruplets, and 34 quintuplets or above) and was compared with those of a control group of unreduced twins. RESULTS: Rates of intrauterine growth restriction per pregnancy were significantly different between the nonreduced and all categories of reduced multifetal pregnancies. The incidence of intrauterine growth restriction was 19.4% in the nonreduced twins, 36.3% in pregnancies reduced from triplets, 41.6% in pregnancies reduced from quadruplets, and 50% from higher-order multiple gestations. There was a statistically significant trend toward increasing frequency of intrauterine growth restriction with increasing starting fetal number (p = 0.04). The increase in intrauterine growth restriction was primarily accounted for by twin pairs with only one growth-restricted newborn. CONCLUSION: Multifetal pregnancy reduction does not reduce the incidence of intrauterine growth restriction in the remaining fetuses to that of nonreduced twins.     

Cerebellar growth in normal and growth-restricted fetuses of multiple gestations

OBJECTIVE: Our purpose was to evaluate growth of the cerebellum in growth-restricted fetuses of twin and triplet gestations versus growth in normal in utero sibling(s) and in singleton gestations. STUDY DESIGN: An ultrasonographic study was conducted in a population of pregnant women with twin and triplet gestations. The control group was either the normal in utero sibling(s) when one fetus was growth restricted or normal twin and singleton pregnancies. Standard biometric measurements were obtained on all fetuses throughout pregnancy, including the transverse cerebellar diameter. However, only the last measurement was used for the analysis. Statistical analyses were conducted comparing growth of the transverse cerebellar diameter among the growth-restricted fetuses versus growth in the normal in utero fetal sibling(s) or other normal twin and singleton gestations. RESULTS: Pregnancies were categorized on the basis of the growth status of women with twin and triplet gestations: Group 1 (151) contained women with two fetuses appropriately grown for gestational age; group 2 (52) had one appropriately grown fetus and one with intrauterine growth restriction; group 3 (19) had two fetuses with intrauterine growth restriction. In addition, there were 30 triplet gestations (group 4), five of which had growth-restricted fetuses, and group 5 contained 1405 singleton pregnancies. In all five groups there was a statistically significant relationship between transverse cerebellar diameter and gestational age (p < 0.0001). There was also no significant difference between growth of the transverse cerebellar diameter in the appropriately grown and growth-restricted siblings and among normal singleton and twin pregnancy groups. In most cases of growth-restricted fetuses, except for the transverse cerebellar diameter measurements, all other biometric parameters were < 10th percentile. CONCLUSION: These data confirm the relative preservation of normal cerebellar growth in growth-restricted fetuses and a similar rate of growth in singleton and multifetal gestations. The transverse cerebellar diameter therefore represents an independent biometric parameter that can be used in both singleton and multifetal pregnancies to assess normal and deviant fetal growth.     

A microscopic analysis of cut-bevel versus pencil-point spinal needles

OBJECTIVE: Our purpose was to establish new nomograms for the birth weight of twins on the basis of accurate methods to validate gestational age. STUDY DESIGN: The medical records of 1632 consecutive twin gestations delivered between 1984 and 1996 were reviewed. Only pregnancies induced by ovulation induction techniques or that were measured ultrasonographically for crown-rump length during the first trimester were included. Excluded were those whose fetuses (one or both) were stillborn, or if the mother smoked, had a significant chronic illness, or was prescribed any regular medications. The study comprised 520 twin pregnancies at 28 to 41 gestational weeks at delivery. RESULTS: The median and 10th and 90th percentile birth weight curves were calculated for the studied twins and plotted against previously reported singleton nomograms. Fetuses of twin pregnancies were found to be growth restricted in comparison with previously reported singletons throughout the third trimester. This trend became more evident after the thirty-fourth to thirty-sixth weeks. CONCLUSIONS: We recommend these novel birth weight nomograms for clinical use in the management of twin pregnancies.     

How accurate is fetal biometry in the assessment of fetal age?

OBJECTIVE: The purpose of the study was to assess the accuracy of fetal biometry in the midtrimester of pregnancy in the assignment of fetal age. STUDY DESIGN: A total of 152 singleton, 67 twin, and 19 triplet gestations resulting from in vitro fertilization with ultrasonographic fetal biometry from 14 to 22 weeks made up the study population. A gestational age prediction equation was derived from singletons with the use of stepwise linear regression. This equation was compared with 38 previously published equations and then applied to the twin and triplet populations. RESULTS: Head circumference was the best predictor of gestational age (random error [SD] 3.77 days). Addition of abdominal circumference and femur length to head circumference improved the accuracy of the dating equation (random error 3.35 days). Most dating formulas had systematic errors of <1 week. The systematic error was -0.32 day for averaging the singleton-based predictions for twins and -1.26 days for triplets. CONCLUSIONS: Gestational age assessment with the use of fetal biometry from 14 to 22 weeks is accurate for singleton, twin, and triplet gestations.     

Neonatal morbidity and mortality associated with triplet pregnancy

OBJECTIVE: To compare neonatal morbidity and mortality in a large cohort of triplet pregnancies with singleton and twin neonates managed at a single tertiary center over a short time. METHODS: Records from all triplet pregnancies managed and delivered from 1992 to 1996 were reviewed for neonatal outcome data. Pregnancies delivered before 20 weeks' gestation and neonates with lethal congenital anomalies were excluded. The comparison group comprised all singleton and twin neonates managed in the same neonatal intensive care unit (NICU) during the same period. RESULTS: During the 5-year period, 55 triplet pregnancies and their resulting 165 neonates were managed and delivered at this center. Their outcomes were compared with those of 959 singleton and 357 twin neonates born at similar gestational ages. The median gestational age at delivery for triplets was 32.1 weeks, and 149 of the 165 infants were admitted. Sixteen triplet neonates were not admitted to our neonatal intensive care unit, 12 because of previable gestational age, three because of stillbirth, and one because of a lethal congenital anomaly. The crude perinatal mortality rate in triplets was 121 per 1000 births, and there was no significant difference in outcome based on triplet birth order. There were no significant differences in survival rates between singleton, twin, and triplet neonates, with an overall neonatal survival of 95%, 95%, and 97%, respectively. The only significant differences in morbidity were an increased incidence of mild intraventricular hemorrhage (relative risk [RR] 6.20; 95% confidence interval [CI] 2.64, 14.61), mild retinopathy of prematurity (RR 20.05; 95% CI 3.59, 111.79), and severe retinopathy of prematurity (RR 46.69; 95% CI 6.25, 348.85) in triplets compared with singletons, and severe retinopathy of prematurity (RR 6.83; 95% CI 1.24, 37.56) in triplets compared with twins. CONCLUSION: When stratified by gestational age, triplet neonates delivered at 24-34 weeks' gestation have similar outcomes as singleton and twin neonates, with the only clinically significant difference being an increased incidence of retinopathy of prematurity in triplets.     

DNA amplification polymorphisms of Mucor piriformis

OBJECTIVE: The aim was to determine the chorionic and amniotic types in multifetal pregnancies with transvaginal ultrasonography at very early stage of gestation. STUDY DESIGN: Twenty-one spontaneous multifetal pregnancies were scanned transvaginally before 8 weeks' gestation (four of them from 4th week). The chorionic and amniotic type was determined ultrasonographically. All twin gestations had postpartum pathologic evaluation of the placenta and histologic determination of the chorionic and amniotic type. RESULTS: Ultrasonographic evaluation of the 21 pregnancies demonstrated 20 twin and 1 triplet gestation. Four of the twin pregnancies were monochorionic-diamniotic. Triplet was monochorionic-triamniotic (spontaneously aborted in 8th week of gestation). In all 20 twin pregnancies, transvaginal ultrasonography correctly predicted the chorionic and amniotic type before 8 weeks of gestation. CONCLUSION: Transvaginal ultrasonography allows a reliable, simple and rapid determination; the dichorionic twin pregnancy in 4 weeks, monochorionic in 5 weeks, and differentiation of mono- or diamniotic in 7 weeks of gestation.     

Effects of fetal number and multifetal reduction on length of in vitro fertilization pregnancies

OBJECTIVE: To determine the effects of multifetal reduction and other variables on the duration of gestation of in vitro fertilization (IVF) pregnancies. METHODS: All 274 IVF pregnancies from the inception of the Women and Infants' Hospital IVF Program on May 26, 1988, until December 31, 1993, were evaluated. RESULTS: Spontaneous reduction occurred in ten pregnancies, and multifetal reduction was elected in 28 multiple gestations. Among 260 pregnancies that remained viable beyond 20 weeks, 162 singletons (37.9 +/- 0.29 weeks; mean +/- standard error) had a longer mean gestation than did 64 twins (34.6 +/- 0.61 weeks), 25 pregnancies reduced to twins (33.4 +/- 1.0 weeks), or nine triplets (29.7 +/- 1.9 weeks). Triplets delivered 4.9 weeks earlier than nonreduced twins (P < .05) and 3.7 weeks before twins resulting from multifetal pregnancy reduction (P < .05). Regression analysis showed that at the 8-week ultrasound, each viable fetus could be expected to reduce the duration of the gestation by about 3.6 weeks, and each fetus reduced medically or as a result of natural causes could be expected to prolong the gestation by approximately 3.0 weeks. Only 14% of triplet pregnancies underwent spontaneous multifetal reduction. CONCLUSION: Multifetal reduction of pregnancies with three or more fetuses was beneficial and increased the duration of gestation.     

Prevalence of cerebral palsy in twins, triplets and quadruplets

BACKGROUND: Twins and triplets are at higher risk of cerebral palsy than singletons. This study investigated the degree of risk for cerebral palsy in twins, triplets and quadruplets, and identified factors associated with the increased risk. METHODS: The subjects were recruited from the Kinki University Twin and Higher Order Multiple Births Registry. RESULTS: The subjects were 705 twins pairs (1410 twins), 96 sets of triplets (287 triplets excluding one infant death), and 7 sets of quadruplets (27 quadruplets excluding one infant death), who were born after 1977. The prevalence of cerebral palsy was 0.9% among 1410 twins, 3.1% among 287 triplets, and 11.1% among 27 quadruplets. Furthermore, the risks of producing at least one child with cerebral palsy were 1.5%, 8.0%, 42.9% in twin, triplet, quadruplet pregnancies, respectively. After adjusting for each associated factor using logistic regression, the risk of cerebral palsy was significantly associated with decrease in gestational age and asphyxia. The odds ratio indicated that infants whose gestational age was < 32 weeks were 20 times more likely to develop cerebral palsy than infants whose gestational age was > or = 36 weeks. CONCLUSIONS: The prevalence of cerebral palsy in triplets and quadruplets was higher than that in twins. Lower gestational age was associated with a greater risk of cerebral palsy.     

Effects of embryo reduction from trichorionic triplets to twins

Sixty-six trichorionic triplet pregnancies reduced to twins were compared with 47 triplet pregnancies that were not reduced. The miscarriage rate was higher (7.6% compared with 2.6%) but the number delivering between 24 and 32 weeks was lower (8.2% compared with 24.0%). Since severe preterm delivery is associated with risks of neonatal death and severe handicap, embryo reduction of triplets to twins may not improve the chance of survival but may reduce the rate of handicap.     

Multifetal pregnancy reduction: modification of the technique and analysis of the outcome

OBJECTIVE: To modify the technique of multifetal pregnancy reduction and to study the outcome of reduced twins in comparison with nonreduced twins and high-order multiple gestations. DESIGN: Prospective controlled study. SETTING: The Egyptian IVF-ET Center, Cairo. PATIENT(S): Seventy-five patients with high-order multiple pregnancies resulting from assisted reproduction. Controls were 40 nonreduced twin pregnancies and 22 high-order multiple gestations. INTERVENTION(S): Transvaginal ultrasonically guided multifetal pregnancy reduction was performed. The first 30 cases were done using KCl as a cardiotoxic agent. The modified technique was used for the last 45 cases at an earlier gestational age (approximately 7 weeks) by eliminating the use of KCI and by aspirating the embryonic parts. MAIN OUTCOME MEASURE(S): Miscarriage rate, gestational age at delivery, birth weight, and pregnancy complications. RESULT(S): Using the modified technique, the miscarriage rate was 8.8% and 41 patients delivered between 32 and 39 weeks of gestation (mean+/-SD, 36.9+/-2.45 weeks). The mean (+/-SD) birth weight was 2,450.51+/-235.44 g. The miscarriage rate, fetal wastage rate, mean gestational age, and mean birth weight were similar in reduced and nonreduced twins and were significantly better than in nonreduced triplets and quadruplets. CONCLUSION(S): The modified technique of multifetal pregnancy reduction significantly improved outcomes, which were similar to those of nonreduced twins resulting from assisted reproduction and significantly better than those of nonreduced triplets and quadruplets.     

Accuracy of ultrasound estimation of fetal weight in multiple pregnancies

Our objective was to assess the accuracy of ultrasonographic estimation of fetal weight in twins and triplets as compared to singleton pregnancies. Retrospective analysis was undertaken of ultrasound data of all fetuses who underwent an examination within 1 week of delivery (singletons 1832, twins 518, triplets 51). At birth weights below 2500 g, there was a significant overestimation of fetal weight in twins as compared to singletons, but the accuracy of the estimate was the same, except in twins between 1500 and 2499 g, when the weight was based on abdominal circumference and femur length alone. At birth weights of more than 2500 g, no difference was detected between twins and singletons. At all birth weights below 2500 g, the accuracy of weight estimation in triplets was equal to that in singletons and there were no triplets above this weight. We conclude that ultrasonographic estimation of fetal weight is as accurate in twins and triplets as it is in singletons.     

Maternal weight gain patterns and birth weight outcome in twin gestation

OBJECTIVE: To evaluate the association between maternal weight gain patterns, based on pregravid body mass index (BMI) and birth weight outcome in twins, and to make specific recommendations for maternal weight gain during twin gestation. METHODS: One hundred eighty-nine twin pregnancies were reviewed retrospectively. Weekly rates of maternal weight gain before 20 weeks, from 20 weeks to delivery, and for total gestation were calculated. Thresholds of weekly maternal weight gain were determined for underweight and normal-weight women. RESULTS: In underweight women, a higher weekly rate of gain before 20 weeks was associated with the birth of both twins weighing at least 2500 g (1.13 versus 0.70 lb/week, P = .017), when compared with mothers of at least one twin weighing less than 2500 g. A higher rate of weight gain from 20 weeks to delivery was associated with the delivery of twins weighing at least 2500 g in both underweight (1.92 versus 1.29 lb/week, P = .031) and normal weight (1.63 versus 1.29 lb/week, P = .046) women. No significant differences in weight gain patterns were found between overweight women delivering twins weighing less than 2500 g or at least 2500 g. A weekly rate of gain from 20 weeks' gestation to delivery of at least 1.75 lb/week in underweight women and at least 1.50 lb/week in normal-weight women was associated with the birth of both twins weighing at least 2500 g. After controlling for other potential determinants of birth weight, the threshold of 1.75 lb/week in underweight women showed a trend toward significance as an independent predictor of both twins weighing at least 2500 g (P = .06). CONCLUSION: Certain maternal weight gain patterns during twin pregnancy are associated with the birth of each twin weighing at least 2500 g. As with singletons, recommendations for maternal weight gain during twin pregnancy can be based on pregravid BMI.     

Circulating maternal serum progesterone in high-risk pregnancies

Serum progesterone was measured by competitive protein-binding assay in 331 cases of normal pregnancy ranging from 6 to 42 weeks. Serial estimations of serum progesterone were performed in nine cases of severe hypertensive disorder of pregnancy, eight cases of twin pregnancy, three cases of twin pregnancy complicated by severe hypertensive disorder of pregnancy, three cases of triplet pregnancy, three cases of previous bad obstetric history, one case of anencephaly, and seven cases of intrauterine fetal death. Serum progesterone remained within normal range in severe hypertensive disorder of pregnancy and the levels were indistinguishable in cases of fetal growth retardation from those without growth retardation. In twin and triplet pregnancies, serum progesterone was within normal range or elevated and was usually higher than normal in twin pregnancies after weeks 33 to 34. Serum progesterone levels were normal in anencephalic pregnancy and in most cases of intrauterine fetal death. The findings are discussed with reference to placental hormonal activity. It is concluded that serum progesterone is a poor index of placental function.     

Conservative management of post-operative peritoneal cysts associated with endometriosis

BACKGROUND: Early amniocentesis has been claimed to confer a higher risk of fetal loss than standard amniocentesis after the 15th gestational week. Our experience of early amniocentesis in single and twin gestations from 1990 - 1995 is presented with 99.3% follow-up. METHODS: Amniocentesis was performed between 11 gestational weeks + 5 days and 14 gestational weeks + 6 days. RESULTS: In 1646 pregnancies 1678 amniocenteses were performed. Thirty-two reamniocenteses were done, 17 due to amniocyte culture failure and 15 due to failure to obtain sufficient amount of amniotic fluid on the first occasion. After puncture 1.49% (25/1678) suffered a spontaneous abortion. Twenty twin pregnancies were included. One spontaneous abortion was noted in this group, as well as three cases where one fetus was normal and the other had a severe defect. Selective abortions were performed without complications. CONCLUSIONS: The difference of postprocedure fetal loss in our population between early and standard amniocentesis is 0.8%. A comparison of postprocedure losses is not appropriate when amniocenteses are performed at a different gestational age, as spontaneous loss decreases with increased gestational age. Our results compare well with the only randomized study between early and standard amniocentesis where the fetal loss after early amniocentesis is similar to that in standard amniocentesis.     

The intrauterine ponderal index in relation to birth weight discordance in twin gestations

OBJECTIVE: To establish the relationship between the fetal ponderal index and birth weight discordance in twins. METHOD: The fetal ponderal index (estimated fetal weight divided by femur length3) was calculated in 86 pairs of twins delivered within 2 weeks of the last sonography and analyzed in relation to birth weight discordance. RESULTS: A weak but significant correlation between fetal ponderal index and birth weight (r = 0.26, P < 0.0007) but no correlation with gestational age (r = 0.035, P = 0.65) were found. Members of concordant pairs (< 15% birth weight difference) had a significantly higher fetal ponderal index compared with members of mildly (15-25%) discordant pairs (P < 0.02), but not as compared with members of severely discordant (> 25%) pairs. CONCLUSION: The characteristics of the fetal ponderal index in twins are similar to those in singletons. Fetal size seems to be diminished in severe but not in mild discordants. However, in its present form, the fetal ponderal index is a poor predictor of discordant growth and therefore should be employed cautiously in twin gestations.     

Prognosis and long-term follow-up of a twin after antenatal death of the co-twin

It is generally believed that among twin pregnancies with one fetal loss prior to delivery, the surviving twin has an increased rate of perinatal mortality and childhood morbidity (cerebral palsy and mental retardation). By using data from the National Medical Birth Registry of Sweden between 1973 and 1983, we identified 206 gestations with the death of at least one twin (in 36 pregnancies both twins died) prior to delivery. The original medical records were retrieved for study. The presence of childhood morbidity for 65 of 129 surviving (8 years of age or older) twins born between 1973 and 1980 was evaluated by a questionnaire sent to rehabilitation centers for disabled children, as well as to offices for the Provision of Care for the Mentally Retarded. Perinatal mortality for a twin after the antenatal death of the co-twin was considerable. Fifty percent of survivors died before 34 weeks' gestation, and 18.7% thereafter. At follow-up, 8 years or more after birth, three twins (4.6%) were handicapped. Our results indicate the need for careful monitoring of the surviving twin fetus after one twin has succumbed prenatally.     

Oocyte donation to women of advanced reproductive age: pregnancy results and obstetrical outcomes in patients 45 years and older

We analysed the results of oocyte donation to women of advanced reproductive age (> or = 45 years old) and followed their pregnancies through to delivery in order to assess obstetrical outcomes. Patients (n = 162) aged 45-59 years (mean +/- SD; 47.3 +/- 3.4 years) underwent 218 consecutive attempts to achieve pregnancy. Oocytes (16.2 +/- 7.2 per retrieval) were provided by donors < or = 35 years old. Cleaving embryos (8.2 +/- 4.8 zygotes/couple) were transferred transcervically (4.5 +/- 1.1 per embryo transfer) to recipients prescribed oral micronized oestradiol and intramuscular progesterone. Following oocyte aspiration there were six instances of non-fertilization (2.8%) and 212 embryo transfers. A total of 103 pregnancies was established for an overall pregnancy rate (PR) of 48.6%, which included 17 preclinical pregnancies, 12 spontaneous abortions, and 74 delivered pregnancies (clinical PR 40.6%; delivered PR 34.9%). Multiple gestations were frequent (n = 29; 39.2% of pregnancies) and included 20 twins, seven triplets, and two quadruplets. Two of the triplet and both of the quadruplet pregnancies underwent selective reduction to twins. Antenatal complications occurred in 28 women (37.8% of deliveries) and included preterm labour (n = 9), gestational hypertension (n = 8), gestational diabetes (n = 6), carpel tunnel syndrome (n = 2), pre-eclampsia (n = 2), HELLP syndrome (n = 2), and fetal growth retardation (n = 2). 48 (64.8%) deliveries were by Caesarean section. The gestational age at delivery for singletons was 38.3 +/- 1.3 weeks (range 35-41 weeks), with birth weight 3218 +/- 513 g (range 1870-4775 g); twins 35.9 +/- 2.0 weeks (range 32-39 weeks), birth weight 2558 +/- 497 g (range 1700-3450 g); and triplets 33.5 +/- 0.7 weeks (range 32-34 weeks), birth weight 1775 +/- 190 g (range 1550-2100 g). Neonatal complications (4.6% of babies born) included growth retardation (n = 2), trisomy 21 (n = 1), ventricular septal defect (n = 1), and small bowel obstruction (n = 1). There were no maternal or neonatal deaths. We conclude that oocyte donation to women of advanced reproductive age is highly successful in establishing pregnancy. However, despite careful antenatal screening, obstetrical complications are common, often secondary to multiple gestation.     

Doppler velocimetry determined redistribution of fetal blood flow: correlation with growth restriction in diamniotic monochorionic and dizygotic twins

OBJECTIVE: Our purpose was to study fetal growth and blood flow distribution in diamniotic monochorionic compared with dizygotic (diamniotic dichorionic) twins by use of Doppler velocimetry of the umbilical artery and middle cerebral artery. STUDY DESIGN: Study candidates were divided into group A, consisting of 33 pairs (66 fetuses) of diamniotic monochorionic twins, and group B, 50 pairs (100 fetuses) of diamniotic dichorionic twins. Diamniotic monochorionic placentation was confirmed by microscopic placental examination for group A. Diamniotic dichorionic placentation was ensured for group B by selecting only twins with different-sex pairs (dizygotic twins). Targeted ultrasonography with biometry was performed in each twin, and Doppler recordings of the umbilical artery and middle cerebral artery were obtained. Waveforms were analyzed and the systolic/diastolic ratio, the resistance index, and a measure of blood flow redistribution (brain-sparing effect), the cerebral/placental ratio, was calculated for each fetus. Growth status at birth was assessed by the number of small-for-gestational-age infants (< or = 10th percentile), low-birth-weight infants (< or = 25th percentile), and percent of growth discordance between twins. Intertwin differences were assessed by delta values (value of larger twin minus value of smaller twin). RESULTS: Diamniotic monochorionic compared with dizygotic twins demonstrated a significantly greater probability of blood flow redistribution. For the study population as a whole, the brain-sparing effect was noted in 67% of small-for-gestational-age babies and only 7% of non-small-for-gestational-age infants (p < or = 0.001). For the diamniotic monochorionic pregnancies blood flow redistribution occurred in 6 of 10 small-for-gestational-age infants (60%) and 6 of 46 non-small-for-gestational-age infants (13%). In the diamniotic monochorionic group small-for-gestational-age compared with non-small-for-gestational-age infants were more likely to show blood flow redistribution, which was the result of significantly decreased resistance in the middle cerebral artery and significantly increased resistance in the umbilical artery. Small-for-gestational-age infants (< or = 10th percentile) occurred much less frequently in the dizygotic group. Two of two small-for-gestational-age infants in the dizygotic group showed blood flow redistribution. Although the extremes of birth weight were more common in the diamniotic monochorionic group, both groups had relatively large numbers of small babies with birth weights in the lower 25th percentile (50.0% for diamniotic monochorionic and 44.0% for dizygotic twins, not significant). However, 42.3% (11/26) of diamniotic monochorionic twins who were in the low-birth-weight group showed blood flow redistribution compared with only 3.3% (1/30) whose birth weights were > or = 25th percentile (p < or = 0.001). In the dizygotic twins 10% of lower-birth-weight infants redistributed blood flow compared with 1% in the higher-birth-weight group, a nonsignificant difference. Diamniotic monochorionic compared with dizygotic twins were delivered earlier (32.9 weeks vs 34.8 weeks, p < or = 0.001), were smaller (1832 gm vs 2304 gm, p < or = 0.001), showed higher birth weight discordance (29.8% vs 14%, p < or = 0.05), and had greater numbers (19.7% vs 2.3%, p < or = 0.01) of infants at < or = 10th percentile birth weight. CONCLUSIONS: Diamniotic monochorionic twins from the lower-birth-weight groups more often show blood flow redistribution compared with dizygotic twins of similar low birth weights. Placental vascular connections and the attendant hemodynamic changes in the fetuses of diamniotic monochorionic twins probably account for this difference. Brain-sparing events occur commonly without clinical twin transfusion syndrome in this group. These findings have implications for management.     

Acute and chronic fetal hypoxia in monochorionic and dichorionic twins

OBJECTIVE: To assess the risk for acute and chronic fetal hypoxia in twin pregnancies. METHODS: We investigated 50 sets of twins (24-38 weeks' gestation, 660-3200 g birth weight) admitted consecutively to our neonatal intensive care unit. Seventy-six infants were appropriate for gestational age (AGA; tenth to 90th percentile), 20 were small for gestational age (SGA; below the tenth percentile), and four were large for gestational age (above the 90th percentile). Twenty-six singleton AGA term newborns served as controls. Umbilical arterial pH was used as a marker for acute and umbilical venous erythropoietin concentration for chronic fetal hypoxia. The results are given as median followed by quartiles. RESULTS: We identified 40 sets of diamniotic-dichorionic twins and ten sets of diamniotic-monochorionic twins with transplacental vascular shunts. In the second-born twin, umbilical arterial pH was lower (7.29, 7.23-7.33) than in the firstborn (7.31, 7.25-7.34) (P = .03), and the incidence of a low pH (less than 7.20) was higher (19 versus 11%). Two second-born twins and none of the firstborn twins had an umbilical arterial pH less than 7.05. In SGA twins, the erythropoietin concentration was elevated (34.8, 22.8-325 mU/mL) compared with that in AGA twins (16.2, 8.2-26.6 mU/mL) (P < .01). In AGA twins, erythropoietin concentration did not differ from that in AGA singleton newborns (19.6, 14.7-31.6 mU/mL). In 12 of 17 twin sets with weight discordancy greater than 15% and in all five twin sets with weight difference greater than 25%, erythropoietin concentration was higher in the smaller twin. The proportion of infants and of complete sets with elevated erythropoietin levels was higher (P < .01) in monochorionic than in dichorionic pregnancies. CONCLUSION: The second-born twin is at increased risk for acute birth asphyxia. Fetal growth restriction in twin pregnancies is associated with chronic fetal hypoxia. Monochorionic twins are at higher risk for chronic fetal hypoxia than are dichorionic twins.     

Iatrogenic multiple pregnancy. Higher risk than a spontaneous one?

OBJECTIVE: To determine if spontaneous and induced multiple pregnancies have similar outcomes. STUDY DESIGN: We compared the results of antepartum and intrapartum surveillance and fetal outcome in spontaneous multiple gestations (group A) with induced multiple gestations (group B) at Albert Szent-Gy?rgyi Medical University, Szeged, Hungary, in a six-year period. RESULTS: Between January 1, 1991, and December 31, 1996, there were 13,131 births; the number of multiple pregnancies was 307 (2.34%). There were 232 spontaneous and 48 induced twin pregnancies, 8 spontaneous and 16 induced triplet pregnancies, and 3 quadruplet pregnancies, all induced. Higher incidences of gestational diabetes and cervical insufficiency were found in group B. The incidences of prematurity in the induced and spontaneous groups were similar. The incidences of low birth weight and perinatal mortality were higher in induced triplet pregnancies than in spontaneous ones. Fetal outcome, with respect to Apgar score and umbilical cord blood pH, was much poorer in both induced groups. CONCLUSION: Iatrogenic multiple pregnancy following ovulation induction or assisted operative reproductive techniques may increase the incidence of pathologic events in the antepartum, intrapartum or postpartum period. Careful counseling before assisted reproductive techniques is of paramount importance.